Spotlight has not been useful to me in over half a decade. It never finds the files I need, despite the fact that I know they're there, I know I typed them right, and I know its settings hasn't hidden or ignored them. And instead it almost always shows useless files in completely obscure parts of the OS that shouldn't even show up in Spotlight. I turned it off like a year ago and haven't regretted it since.
Interesting- I find it very useful. It even searches my email that is locally cached. Lots of apps create hooks into it. Major part of the ecosystem that makes MacOS what it is.